[Qemu-commits] [qemu/qemu] 20eee6: target/hppa: Fix PSW V-bit packaging in cpu_hppa_g...

[Helge Deller]

  Branch: refs/heads/staging-9.1
  Home:   https://github.com/qemu/qemu
  Commit: 20eee6cb3d3d75a471fbf200c68441893aa5491a
      
https://github.com/qemu/qemu/commit/20eee6cb3d3d75a471fbf200c68441893aa5491a
  Author: Helge Deller <deller@gmx.de>
  Date:   2024-09-05 (Thu, 05 Sep 2024)

  Changed paths:
    M target/hppa/cpu.h
    M target/hppa/helper.c

  Log Message:
  -----------
  target/hppa: Fix PSW V-bit packaging in cpu_hppa_get for hppa64

While adding hppa64 support, the psw_v variable got extended from 32 to 64
bits.  So, when packaging the PSW-V bit from the psw_v variable for interrupt
processing, check bit 31 instead the 63th (sign) bit.

This fixes a hard to find Linux kernel boot issue where the loss of the PSW-V
bit due to an ITLB interruption in the middle of a series of ds/addc
instructions (from the divU milicode library) generated the wrong division
result and thus triggered a Linux kernel crash.

Link: 
https://lore.kernel.org/lkml/718b8afe-222f-4b3a-96d3-93af0e4ceff1@roeck-us.net/
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 931adff31478 ("target/hppa: Update cpu_hppa_get/put_psw for hppa64")
Cc: qemu-stable@nongnu.org # v8.2+
(cherry picked from commit ead5078cf1a5f11d16e3e8462154c859620bcc7e)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>



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